@inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Geiger, M. and Sader, Robert and Zeilhofer, Hans-Florian}, title = {How does the periodontal ligament influence overall stress/strain profiles of a partially edentulous mandible?}, booktitle = {Proc. of 8th Int. Conference on Biological Mechanisms of Tooth Eruption, Resorption and Movement, Phuket, Thailand}, editor = {Davidovitch, Z. and Mah, J. and Suthanarak, S.}, address = {Harvard Society of the Advancement of Orthodontics, Boston, Massachusetts, USA}, year = {2005}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2004, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Anisotropic Simulation of the Human Mandible}, booktitle = {Proc. of 17th ASCE Engineering Mechanics Conference}, publisher = {Univ. of Delaware}, year = {2004}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Consideration of Bone Inhomogeneity and Anisotropy in Deformation Analysis of a Human Mandible}, volume = {1}, booktitle = {Proc. of BMT2005, 39th Annual Congress of the German Society of Biomedical Engineering, Nuremberg, Germany}, editor = {Boenick, U. and Bolz, A.}, publisher = {VDE}, address = {Nuremberg, Germany}, pages = {814 -- 815}, year = {2005}, language = {en} } @inproceedings{KoberErdmannHellmichetal.2005, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {The Influence of the Periodontal Ligament on Overall Stress/Strain Profiles of a Human Mandible}, booktitle = {Proc. of 23rd CADFEM Users' Meeting, Int. Congress on FEM Technology, Biomechanics}, editor = {CADFEM GmbH, Grafing}, address = {Bonn, Germany}, pages = {1 -- 10}, year = {2005}, language = {en} } @article{KoberErdmannHellmichetal.2006, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Consideration of anisotropic elasticity minimizes volumetric rather than shear deformation in human mandible}, volume = {9(2)}, journal = {Comp. Meth. Biomech. Biomed. Eng.}, pages = {91 -- 101}, year = {2006}, language = {en} } @article{KoberErdmannHellmichetal.2006, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Validation of interdependency between inner structure visualization and structural mechanics simulation}, journal = {Int. Poster J. Dent. Oral Med.}, year = {2006}, language = {en} } @article{KoberErdmannHellmichetal.2006, author = {Kober, C. and Erdmann, Bodo and Hellmich, Christian and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Validation of interdependency between inner structure visualization and structural mechanics simulation}, journal = {Int. Poster J. Dent. Oral Med.}, year = {2006}, language = {en} } @inproceedings{KoberErdmannLangetal.2004, author = {Kober, C. and Erdmann, Bodo and Lang, Jens and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Sensitivity of the Temporomandibular Joint Capsule for the Structural Behaviour of the Human Mandible}, volume = {49-2}, booktitle = {Proc. BMT 2004}, address = {Ilmenau, Deutschland}, pages = {372 -- 373}, year = {2004}, language = {en} } @article{DeuflhardErdmannRoitzschetal.2009, author = {Deuflhard, Peter and Erdmann, Bodo and Roitzsch, Rainer and Lines, Glenn Terje}, title = {Adaptive Finite Element Simulation of Ventricular Dynamics}, volume = {12}, journal = {J. Computing and Visualization in Science}, pages = {201 -- 205}, year = {2009}, language = {en} } @inproceedings{KoberErdmannLangetal.2004, author = {Kober, C. and Erdmann, Bodo and Lang, Jens and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Adaptive Finite Element Simulation of the Human Mandible Using a New Physiological Model of the Masticatory Muscles}, volume = {4}, booktitle = {Proc. of 75th Annual Meeting of the GAMM}, number = {1}, pages = {332 -- 333}, year = {2004}, language = {en} } @inproceedings{KoberErdmannSaderetal.2003, author = {Kober, C. and Erdmann, Bodo and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Simulation of the Human Mandible}, booktitle = {Proceedings of 10th Workshop on The Finite Element Method in Biomedical Engineering, Biomechanics and Related Fields}, address = {Ulm, Germany}, year = {2003}, language = {en} } @article{KoberErdmannSaderetal.2003, author = {Kober, C. and Erdmann, Bodo and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Belastungssimulation beim menschlichen Biss im Vergleich mit der Dichtestruktur im Unterkieferknochen}, volume = {48}, journal = {Biomedizinische Technik}, number = {Erg{\"a}nzungsband 1}, pages = {268 -- 269}, year = {2003}, language = {en} } @inproceedings{KoberErdmannSaderetal.2004, author = {Kober, C. and Erdmann, Bodo and Sader, Robert and Zeilhofer, Hans-Florian}, title = {An Application of Adaptive Finite Element Techniques in Biomechanics}, booktitle = {22. CAD-FEM Users Meeting - Internationale FEM Technologietage}, address = {Dresden, Germany}, year = {2004}, language = {en} } @article{KoberStuebingerErdmannetal.2006, author = {Kober, C. and St{\"u}binger, S. and Erdmann, Bodo and Hellmich, Christian and Radtke, Thomas and Sader, Robert and Zeilhofer, Hans-Florian}, title = {Finite element simulation of the human mandible}, journal = {Int. Poster J. Dent. Oral Med.}, year = {2006}, language = {en} } @inproceedings{RoitzschLangErdmann1998, author = {Roitzsch, Rainer and Lang, Jens and Erdmann, Bodo}, title = {The Benefits of Modularization}, booktitle = {Proc. 14th GAMM-Seminar Kiel on 'Concepts of Numerical Software}, publisher = {did not appear}, year = {1998}, language = {en} } @article{WeiserDeuflhardErdmann2007, author = {Weiser, Martin and Deuflhard, Peter and Erdmann, Bodo}, title = {Affine conjugate adaptive Newton methods for nonlinear elastomechanics}, volume = {22}, journal = {Opt. Meth. Softw.}, number = {3}, pages = {413 -- 431}, year = {2007}, language = {en} } @article{SchenklMuggenthalerHubigetal.2017, author = {Schenkl, Sebastian and Muggenthaler, Holger and Hubig, Michael and Erdmann, Bodo and Weiser, Martin and Zachow, Stefan and Heinrich, Andreas and G{\"u}ttler, Felix Victor and Teichgr{\"a}ber, Ulf and Mall, Gita}, title = {Automatic CT-based finite element model generation for temperature-based death time estimation: feasibility study and sensitivity analysis}, volume = {131}, journal = {International Journal of Legal Medicine}, number = {3}, doi = {doi:10.1007/s00414-016-1523-0}, pages = {699 -- 712}, year = {2017}, abstract = {Temperature based death time estimation is based either on simple phenomenological models of corpse cooling or on detailed physical heat transfer models. The latter are much more complex, but allow a higher accuracy of death time estimation as in principle all relevant cooling mechanisms can be taken into account. Here, a complete work flow for finite element based cooling simulation models is presented. The following steps are demonstrated on CT-phantoms: • CT-scan • Segmentation of the CT images for thermodynamically relevant features of individual geometries • Conversion of the segmentation result into a Finite Element (FE) simulation model • Computation of the model cooling curve • Calculation of the cooling time For the first time in FE-based cooling time estimation the steps from the CT image over segmentation to FE model generation are semi-automatically performed. The cooling time calculation results are compared to cooling measurements performed on the phantoms under controlled conditions. In this context, the method is validated using different CTphantoms. Some of the CT phantoms thermodynamic material parameters had to be experimentally determined via independent experiments. Moreover the impact of geometry and material parameter uncertainties on the estimated cooling time is investigated by a sensitivity analysis.}, language = {en} } @article{WeiserFreytagErdmannetal.2018, author = {Weiser, Martin and Freytag, Yvonne and Erdmann, Bodo and Hubig, Michael and Mall, Gita}, title = {Optimal Design of Experiments for Estimating the Time of Death in Forensic Medicine}, volume = {34}, journal = {Inverse Problems}, number = {12}, doi = {10.1088/1361-6420/aae7a5}, pages = {125005}, year = {2018}, abstract = {Estimation of time of death based on a single measurement of body core temperature is a standard procedure in forensic medicine. Mechanistic models using simulation of heat transport promise higher accuracy than established phenomenological models in particular in nonstandard situations, but involve many not exactly known physical parameters. Identifying both time of death and physical parameters from multiple temperature measurements is one possibility to reduce the uncertainty significantly. In this paper, we consider the inverse problem in a Bayesian setting and perform both local and sampling-based uncertainty quantification, where proper orthogonal decomposition is used as model reduction for fast solution of the forward model. Based on the local uncertainty quantification, optimal design of experiments is performed in order to minimize the uncertainty in the time of death estimate for a given number of measurements. For reasons of practicability, temperature acquisition points are selected from a set of candidates in different spatial and temporal locations. Applied to a real corpse model, a significant accuracy improvement is obtained already with a small number of measurements.}, language = {en} } @misc{WeiserFreytagErdmannetal.2018, author = {Weiser, Martin and Freytag, Yvonne and Erdmann, Bodo and Hubig, Michael and Mall, Gita}, title = {Optimal Design of Experiments for Estimating the Time of Death in Forensic Medicine}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-67247}, year = {2018}, abstract = {Estimation of time of death based on a single measurement of body core temperature is a standard procedure in forensic medicine. Mechanistic models using simulation of heat transport promise higher accuracy than established phenomenological models in particular in nonstandard situations, but involve many not exactly known physical parameters. Identifying both time of death and physical parameters from multiple temperature measurements is one possibility to reduce the uncertainty significantly. In this paper, we consider the inverse problem in a Bayesian setting and perform both local and sampling-based uncertainty quantification, where proper orthogonal decomposition is used as model reduction for fast solution of the forward model. Based on the local uncertainty quantification, optimal design of experiments is performed in order to minimize the uncertainty in the time of death estimate for a given number of measurements. For reasons of practicability, temperature acquisition points are selected from a set of candidates in different spatial and temporal locations. Applied to a real corpse model, a significant accuracy improvement is obtained already with a small number of measurements.}, language = {en} } @article{WeiserErdmannSchenkletal.2018, author = {Weiser, Martin and Erdmann, Bodo and Schenkl, Sebastian and Muggenthaler, Holger and Hubig, Michael and Mall, Gita and Zachow, Stefan}, title = {Uncertainty in Temperature-Based Determination of Time of Death}, volume = {54}, journal = {Heat and Mass Transfer}, number = {9}, publisher = {Springer}, doi = {10.1007/s00231-018-2324-4}, pages = {2815 -- 2826}, year = {2018}, abstract = {Temperature-based estimation of time of death (ToD) can be per- formed either with the help of simple phenomenological models of corpse cooling or with detailed mechanistic (thermodynamic) heat transfer mod- els. The latter are much more complex, but allow a higher accuracy of ToD estimation as in principle all relevant cooling mechanisms can be taken into account. The potentially higher accuracy depends on the accuracy of tissue and environmental parameters as well as on the geometric resolution. We in- vestigate the impact of parameter variations and geometry representation on the estimated ToD based on a highly detailed 3D corpse model, that has been segmented and geometrically reconstructed from a computed to- mography (CT) data set, differentiating various organs and tissue types.}, language = {en} } @misc{LangErdmannRoitzsch1997, author = {Lang, Jens and Erdmann, Bodo and Roitzsch, Rainer}, title = {Three-Dimensional Fully Adaptive Solution of Thermo-Diffusive Flame Propagation Problems}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-2879}, number = {SC-97-18}, year = {1997}, abstract = {In this paper we present a self--adaptive finite element method to solve flame propagation problems in 3D. An implicit time integrator of Rosenbrock type is coupled with a multilevel approach in space. The proposed method is applied to an unsteady thermo--diffusive combustion model to demonstrate its potential for the solution of complicated problems.}, language = {en} } @misc{AckermannErdmannRoitzsch1994, author = {Ackermann, J{\"o}rg and Erdmann, Bodo and Roitzsch, Rainer}, title = {A self-adaptive multilevel finite element method for the stationary Schr{\"o}dinger equation in three space dimensions.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1403}, number = {SC-94-10}, year = {1994}, abstract = {An error controlled finite elemente method (FEM) for solving stationary Schr{\"o}dinger equations in three space dimensions is proposed. The method is based on an adaptive space discretization into tetrahedra and local polynomial basis functions of order \$p=1\$--\$5\$ defined on these tetrahedra. According to a local error estimator the triangulation is automatically adapted to the solution. Numerical results for standard problems appearing in vibrational motion and molecular structure calculations are presented and discussed. Relative precisions better than 1e-8 are obtained. For equilateral H\$_3^{++}\$ the adaptive FEM turns out to be superior to global basis set expansions in the literature. Our precise FEM results exclude in a definite manner the stability or metastability of equilateral H\$_3^{++}\$ in its groundstate.}, language = {en} } @misc{BornemannErdmannKornhuber1993, author = {Bornemann, Folkmar A. and Erdmann, Bodo and Kornhuber, Ralf}, title = {A Posteriori Error Estimates for Elliptic Problems.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1257}, number = {SC-93-29}, year = {1993}, abstract = {{\def\enorm {\mathop{\mbox{\boldmath{\$|\!|\$}}}\nolimits} Let \$u \in H\$ be the exact solution of a given self--adjoint elliptic boundary value problem, which is approximated by some \$\tilde{u} \in {\cal S}\$, \$\cal S\$ being a suitable finite element space. Efficient and reliable a posteriori estimates of the error \$\enorm u - \tilde{u}\enorm \$, measuring the (local) quality of \$\tilde{u}\$, play a crucial role in termination criteria and in the adaptive refinement of the underlying mesh. A well--known class of error estimates can be derived systematically by localizing the discretized defect problem using domain decomposition techniques. In the present paper, we provide a guideline for the theoretical analysis of such error estimates. We further clarify the relation to other concepts. Our analysis leads to new error estimates, which are specially suited to three space dimensions. The theoretical results are illustrated by numerical computations.}}, language = {en} } @misc{ErdmannHoppeKornhuber1993, author = {Erdmann, Bodo and Hoppe, Ronald H. W. and Kornhuber, Ralf}, title = {Adaptive Multilevel-Methods for Obstacle Problems in Three Space Dimensions.}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-1049}, number = {SC-93-08}, year = {1993}, abstract = {We consider the discretization of obstacle problems for second order elliptic differential operators in three space dimensions by piecewise linear finite elements. Linearizing the discrete problems by suitable active set strategies, the resulting linear sub--problems are solved iteratively by preconditioned cg--iterations. We propose a variant of the BPX preconditioner and prove an \$O(j)\$ estimate for the resulting condition number. To allow for local mesh refinement we derive semi--local and local a posteriori error estimates. The theoretical results are illustrated by numerical computations.}, language = {en} }